Fifty,
Consider the research and development as some things were being done for the first time....things were also being made smaller than ever before.
There's also the changing attitudes toward these things with everyone having them these days combined with that making it a cut-throat business, and this leads to lower quality of manufacture.
Furthermore, computers are being used to design computers now in ways not done in the early days. Combined with general experience in designing them, things must be easier than before.